Robotic manipulator having four parallel kinematic

Abstract

A robotic manipulator (M) having four parallel kinematic arms, in particular a delta robot, comprising a support frame and four manipulator arms. Each arm comprises a first segment (200a) comprising a first end (200a') connected to the support frame and a second end (200a''), and a second segment (200b) comprising a first end (200b') connected to the second end (200a'') of the first segment (200a) and a second end (200b''). The manipulator (M) further comprises a movable support (300) on which an operating member is mounted or mountable. The second ends (200b'') of the second segments (200b) are hinged to the movable support (300). Each of the first segments (200a) is connected to the support frame in a rotatable manner about a respective main axis of rotation (X1, X2, X3, X4) so as to move the movable support (300). The main axes of rotation (X1, X2, X3, X4) lie on at least two positioning axes (G1, G2) parallel to each other.

Description

[0001] DESCRIPTION ROBOTIC MANIPULATOR HAVING FOUR PARALLEL KINEMATIC ARMS

[0002] Technical field

[0003] The present invention concerns a robotic manipulator having four parallel kinematic arms that can be used in all situations in which the handling of items is required, such as, for example, containers, sheets, semi-finished products, or discrete items. In particular, the manipulator of the present invention is of the delta robot type, in particular of the quadrupod type.

[0004] Background art

[0005] To date, robotic manipulators are known to be typically arranged along processing lines to handle products or semi-finished products.

[0006] Generally, known parallel kinematics manipulators are provided with a support structure with which two or more movable arms, identical or similar to each other, are operatively associated and each connected to a single gripping terminal member, also known as an “end-effector”, which can be shaped or contoured in various ways in relation to the type of use and / or the type of item to be handled.

[0007] To date, so-called delta robots, which comprise three identical motorized arms arranged on as many planes angled between each other, are particularly widespread. Delta robots allow the translation of the endeffector in the three spatial directions. Some delta robots can comprise four arms that utilize complex and heavy mechanisms to obtain rotational movements of the end-effector.

[0008] To date, so-called duopods, which further comprise three coplanar motorized arms and an end-effector that is moved on a single plane (the same as the arms) and caused to oscillate with respect to an axis perpendicular to the plane, are also widespread.

[0009] Further simplified versions of duopods are also known, wherein there are only two independently motorized arms and a passive jointed parallelogram mechanism to angularly constrain the end-effector. In such a situation, to add the third translation direction, such duopods are mounted on a linear guide or rail.

[0010] Disadvantageously, to achieve the aforesaid degrees of freedom, known manipulators are usually equipped with a motorization on the end-effector and / or particularly complex transmissions. This causes the onset of issues related to the weight of the manipulator and mechanical play in the rotation movements.

[0011] Object of the invention

[0012] Therefore, it is the technical task of the present invention to provide a robotic manipulator having four parallel kinematic arms capable of overcoming the drawbacks emerged from the prior art.

[0013] It is thus the object of the present invention to provide a robotic manipulator having four parallel kinematic arms which is mechanically simple and reliable.

[0014] It is a further object of the present invention to provide a robotic manipulator having four parallel kinematic arms of small size and weight.

[0015] It is a further object of the present invention to provide a fast robotic manipulator having four parallel kinematic arms capable of handling large volumes of work.

[0016] It is a further object of the present invention to provide a robotic manipulator having four parallel kinematic arms not affected by kinematic singularities.

[0017] The specified technical task and the specified objects are substantially achieved by a robotic manipulator having four parallel kinematic arms comprising the technical features set forth in one or more of the appended claims. The dependent claims correspond to possible embodiments of the invention.

[0018] In particular, the specified technical task and the specified objects are achieved by a robotic manipulator having four parallel kinematic arms, in particular a delta robot, according to the present invention.

[0019] The robotic manipulator having four parallel kinematic arms according to the present invention comprises a support frame, for example, a support plate.

[0020] The robotic manipulator further comprises four manipulator arms each comprising a first segment comprising a first end connected to the support frame and a second end.

[0021] Preferably, each first segment is defined by a flexurally and torsionally rigid lever or crank.

[0022] Each of the manipulator arms further comprises a second segment comprising a first end connected to the second end of the first segment and a second end.

[0023] Each first end of each second segment is connected, with a connection having at least two degrees of freedom, preferably two degrees of freedom, and even more preferably hinged by a hinge having two degrees of freedom, to the second end of the first segment.

[0024] Preferably, the first end of each second segment is hinged to the second end of a respective first segment.

[0025] In the present discussion, the term “hinged” can be understood as being connected by a hinge, preferably with at least two degrees of freedom, or by a double hinge, i.e., a universal joint.

[0026] In accordance with an embodiment, the first end of each second segment is connected to the second end of a respective first segment so that there are two degrees of freedom between the first and the second segment.

[0027] In accordance with another embodiment, the first end of each second segment is connected to the second end of a respective first segment by a universal joint, for example, a universal joint with intersecting axes or a universal joint with skew axes. In particular, such a hinging is provided to allow oscillation with two degrees of freedom.

[0028] In accordance with a possible embodiment, each first and / or second segment can be defined by a single rod or by a pair of rods parallel to one another.

[0029] Preferably, the rods or the rod can be hollow.

[0030] Preferably, if the second segments of the manipulator arms are defined by a single rod, the latter is torsionally rigid and preferably hollow.

[0031] Preferably, the second segments of at least two of the manipulator arms are defined by a respective pair of rods parallel to one another. Preferably, the first segments of the four manipulator arms all have the same length and / or the second segments of the four manipulator arms all have the same length.

[0032] The manipulator further comprises a movable support on which an operating member, such as, for example, a caliper, a suction cup, and the like, i.e., any member capable of grasping, holding, and releasing an item, is mounted or mountable.

[0033] The second ends of the second segments are hinged to the movable support.

[0034] Preferably, the second ends of the second segments are hinged to the movable support by means of the same type of hinge by means of which the first ends of the second segments are hinged to the second ends of the first segments.

[0035] In other words, on the two ends of the second segments, there is the same type of hinge, for example, there is the same type of universal joint.

[0036] In greater detail, it is possible that all the first ends of the second segments are hinged to the second ends of the first segments by means of the same type of hinge, and thus also the second ends of the second segments are hinged to the movable support by means of such a type of hinge. Alternatively, it is possible that, for example, the first ends of two of the second segments are hinged to the second ends of the first segments by means of a first type of hinge, and the first ends of the other two second segments are hinged to the second ends of the first segments by means of a second type of hinge. In such a situation, two of the corresponding second ends of the second segments are hinged to the movable support by means of the first type of hinge, and two of the corresponding second ends of the second segments are hinged to the movable support by means of the second type of hinge.

[0037] Preferably, between the second end of each first segment and the respective first end of the second segment, there is a universal joint specular to the one between the second end of each second segment and the movable support.

[0038] The term “specular” means that, observing the universal joints at the ends of a second segment, the two innermost axes of rotation are parallel to each other, and the two outermost axes of rotation are parallel to each other (and perpendicular to the other two axes of rotation).

[0039] Preferably, the second ends of the second segments are connected to the movable support by means of universal joints.

[0040] Alternatively, the second ends of the second segments are connected to the movable support by means of hinges having two degrees of freedom.

[0041] Preferably, the second ends of the second segments are hinged to the movable support so as to be rotatable about respective axes of rotation that are parallel to each other.

[0042] Preferably, the second segments are connected to a same side of the movable support, in particular at connection points arranged at the vertices of a quadrilateral other than a rectangle or a square, preferably at the vertices of a trapezium.

[0043] Alternatively, the second segments are connected to a same side of the movable support at connection points that are not coplanar with each other.

[0044] Alternatively, at least one of the second segments is connected to a first side of the movable support, and at least another of the second segments is connected to a second side of the movable support opposite the first side. In the preferred embodiment, two second segments are connected to the first side of the movable support, and another two second segments are connected to the second side of the movable support. In the preferred embodiment, the movable support is made in the form of a rigid body, in particular in the form of a rigid plate or a rigid disc.

[0045] The movable support can have any shape in plan and in section.

[0046] To move the movable support, each of the first segments is connected to the support frame in a rotatable manner about a respective main axis of rotation. In such a situation, by rotating one or more first segments about the respective main axis of rotation, it is possible to move the movable support in space. In particular, it is possible, by conveniently rotating the first segments, to move the movable support translationally along the three space dimensions and rotate such a movable support about one of them.

[0047] The main axes of rotation lie on at least two distinct and parallel positioning axes.

[0048] Preferably, the main axes of rotation lie on two distinct and parallel positioning axes.

[0049] Even more preferably, two of the main axes of rotation lie on one of the two positioning axes, while the other two main axes of rotation lie on the other positioning axis.

[0050] In accordance with an embodiment, the main axes of rotation are parallel to the axes of rotation about which the second ends of the second segments are rotatable.

[0051] In the illustrated embodiment in which the second ends of the second segments have universal joints, in particular universal joints with skew axes. Each of the universal joints defines a pair of axes of rotation. In such a situation, an axis of rotation of the pair is parallel to a respective main axis of rotation.

[0052] With reference to the illustrated embodiment, for example shown in Figures 1 -4, wherein the first and second ends of the second segments feature universal joints with skew axes, it is noted that the axis of the universal joint at the first end of the second segment and closer to the first segment and the axis of the universal joint at the second end of the second segment and closer to the operating member are parallel to the respective main axis.

[0053] In the preferred embodiment, a first pair of first segments lie on a first plane while the first segments of a second pair lie on a second plane, preferably parallel to the first plane.

[0054] The second segments connected to the first segments of the first pair are incident in a first virtual center of instantaneous rotation, while the second segments connected to the first segments of the second pair are incident in a second virtual center of instantaneous rotation. The first and second virtual centers of instantaneous rotation, projected onto the same plane between the first or the second plane, are not coincident with each other. Preferably, the aforementioned projections are located at different heights on the plane.

[0055] Preferably, the manipulator further comprises four motors activatable independently of each other. Each motor is connected to the first end of a respective first segment so as to rotate the respective first segment about the respective axis of rotation.

[0056] Brief description of the drawings

[0057] Further features and advantages of the present invention will become clearer from the indicative, and therefore non-limiting, description of an embodiment of a robotic manipulator having four parallel kinematic arms.

[0058] Such a description will be set out below with reference to the accompanying drawings, provided merely for indicative and therefore nonlimiting purposes, in which:

[0059] Figure 1 shows a perspective view of a manipulator according to the present invention;

[0060] Figure 1 A shows an enlargement of a detail of Figure 1 ;

[0061] Figure 2 shows a front view of the manipulator in Figure 1 ;

[0062] Figure 3 shows a side view of the manipulator in Figure 1 ;

[0063] Figure 4 shows a top view of the manipulator in Figure 1 ;

[0064] Figure 5 shows a diagrammatic view of an embodiment of the manipulator according to the present invention in two different operating positions;

[0065] Figures 6A and 6B show diagrammatic views of the manipulator in Figure 5 in other operating positions;

[0066] Figures 7A and 7B show diagrammatic views of a further embodiment of the manipulator according to the present invention in different operating positions;

[0067] Figure 7C shows a diagrammatic perspective view of the manipulator in Figures 7A and 7B;

[0068] Figures 8A-8D show diagrammatic perspective views of different embodiments of the manipulator according to the present invention.

[0069] With reference to the accompanying Figures, “M” indicates a robotic manipulator having four parallel kinematic arms, in particular a delta robot.

[0070] Detailed description of preferred embodiments of the invention

[0071] The manipulator “M” comprises a support frame. In the accompanying Figures, the support frame has been partially shown.

[0072] The manipulator “M” comprises four manipulator arms, each comprising a first segment 200a comprising a first end 200a’ connected to the support frame and a second end 200a”.

[0073] Each manipulator arm further comprises a second segment 200b comprising a first end 200b’ connected to the second end 200a” of the first segment 200a and a second end 200b”.

[0074] Each first end 200b’ of each second segment 200b is connected, with a connection having at least two degrees of freedom, preferably two degrees of freedom, and even more preferably hinged by a hinge having two degrees of freedom, to the second end 200a’ of the first segment 200a.

[0075] Preferably, the first end 200b’ of each second segment 200b is hinged to a respective second end 200a” of the first segments 200a.

[0076] Preferably, between each first segment 200a and the respective second segment 200b, there are two degrees of freedom, i.e., the hinge which connects the second end 200a” of each first segment 200a to the first end 200b’ of the respective second segment 200b is a hinge with two degrees of freedom.

[0077] Even more preferably, the first end 200b’ of each second segment 200b is connected to a respective second end 200a” of the first segments 200a by a universal joint.

[0078] In the present description, the term “hinged” can be understood as connected by a hinge, preferably with at least two degrees of freedom, or by a double hinge, i.e., by a universal joint.

[0079] In the illustrated embodiment, the first segments 200a of the four manipulator arms all have the same length, and the second segments 200b of the four manipulator arms all have the same length.

[0080] Preferably, each second segment 200b can be defined by a single rod or by a pair of rods parallel to each another.

[0081] In the illustrated embodiments, each first segment 200a is defined by a single rod.

[0082] As for the second segments 200b, for example in Figure 8A, two of the second segments 200b are defined by a single rod, while the other two of the second segments 200b are defined by a pair of rods parallel to each another. In Figure 8B, however, all the second segments 200b are defined by a pair of rods parallel to each another.

[0083] The manipulator “M” further comprises a movable support 300 on which an operating member is mounted or mountable (not shown in the accompanying figures).

[0084] The term “operating member” means, by way of non-limiting example, a caliper, a suction cup, and the like, i.e., any working member capable of processing (grasping, holding, and releasing) an article or semi-finished product.

[0085] Preferably, the movable support 300 is made in the form of a rigid body, in particular in the form of a rigid plate or a rigid disc. The movable support 300 is therefore not deformable.

[0086] By way of example, in the embodiment shown in Figures 1 -4, the movable support 300 is made in the form of a rectangular plate.

[0087] Alternatively, again by way of example, in Figures 5, 6A, and 6B, the movable support 300 is made in the form of a plate having a prismatic shape with a triangular section.

[0088] Alternatively, again by way of explanation, in Figures 7A-7C, the movable support 300 is made in the form of a plate with a trapezoidal shape.

[0089] As shown in the accompanying Figures, the second ends 200b” of the second segments 200b are hinged to the movable support 300.

[0090] Preferably, the second ends 200b” of the second segments 200b are hinged to the movable support 300 by means of a respective hinge having two degrees of freedom. Such an aspect, together with the aspect according to which the first arms 200a are connected to the second arms 200b by means of respective hinges having two degrees of freedom, allows the movable support 300 to be made as a rigid body since there is no need for any mechanism between the first and second segments 200a, 200b.

[0091] Preferably, the second ends 200b” of the second segments 200b are hinged to the movable support 300 by means of the same type of hinge by means of which the first ends 200b’ of the second segments 200b are hinged to the second ends 200a” of the first segments 200a.

[0092] For example, in Figure 8C, the first ends 200b’ of two of the second segments 200b are hinged to the second ends 200a” of the first segments 200a by means of a first type of hinge, and the first ends 200b’ of the other two second segments 200b are hinged to the second ends 200a” of the first segments 200a by means of a second type of hinge. In such a situation, two of the corresponding second ends 200b” of the second segments 200b are hinged to the movable support 300 by means of the first type of hinge, and two of the corresponding second ends 200b” of the second segments 200b are hinged to the movable support 300 by means of the second type of hinge.

[0093] Another example is shown in Figure 8D, wherein all the first ends 200b’ of the second segments 200b are hinged to the second ends 200a” of the first segments 200a by means of the same type of hinge, and thus the second ends 200b” of the second segments 200b are also hinged to the movable support 300 by means of such a type of hinge.

[0094] Preferably, the second ends 200b” of the second segments 200b are connected to the movable support 300 by means of universal joints (such as, for example, shown in Figure 8D). In accordance with a possible embodiment, shown for example in Figures 7A-7C, the second segments 200b are connected to a same side of the movable support 300. In particular, the second segments 200b are connected to the movable support 300 at connection points arranged at the vertices of a quadrilateral other than a rectangle and a square, preferably at the vertices of a trapezium (Figure 7C).

[0095] Alternatively, such as, for example, shown in Figure 6A and 6B, the second segments 200b are connected to the movable support at connection points that are not coplanar with each other.

[0096] Alternatively, at least one of the second segments 200b is connected to a first side of the movable support 300, and at least another of the second segments 200b is connected to a second side of the movable support 300 opposite the first side.

[0097] Preferably, as shown, for example, in particular in Figure 3, two second segments 200b are connected to the first side of the movable support 300, and another two second segments 200b are connected to the second side of the movable support 300.

[0098] So as to move the movable support 300, each of the first segments 200a is connected to the support frame in a rotatable manner about a respective main axis of rotation “X1”, “X2”, “X3”, “X4”.

[0099] In particular, each of the first segments 200a is rotatable about the first end 200a’ connected to the support frame. The main axes of rotation “X1”, “X2”, “X3”, “X4” lie on at least two distinct and parallel positioning axes “G1”, “G2”.

[0100] Preferably, the main axes of rotation “X1”, “X2”, “X3”, “X4” lie on two distinct and parallel positioning axes “G1”, “G2”.

[0101] Even more preferably, as shown in the accompanying Figures, two of the main axes of rotation “X1”, “X2” lie on one of the two positioning axes “G1 ” while the other two main axes of rotation “X3”, “X4” lie on the other positioning axis “G2”.

[0102] In such a situation, as shown, for example, in Figure 7C, the axes of rotation “X1”, “X2”, “X3”, “X4” are all mutually parallel and are aligned in pairs along the two separate and parallel positioning axes “G1”, “G2”.

[0103] In accordance with the preferred embodiment, the first segments 200a of the four manipulator arms are arranged so that at least two of the first segments 200a are movable, and in particular rotatably movable, on respective planes parallel to and spaced from each other. In accordance with the preferred embodiment, the second ends 200b” of the second segments 200b are hinged to the movable support 300 so as to be rotatable about respective axes of rotation “Y1”, “Y2”, “Y3”, “Y4” parallel to one other. In such a situation, by rotating one or more manipulator arms about the respective main axis of rotation “X1”, “X2”, “X3”, “X4”, it is possible to cause the rotation of the second ends 200b” of the second segments 200b about the axes of rotation “Y1”, “Y2”, “Y3”, “Y4” so as to cause a movement of the movable support 300 in space, as will be described below.

[0104] In the preferred embodiment, the axes of rotation “Y1”, “Y2”, “Y3”, “Y4” are further parallel to the main axes of rotation “Y1”, “Y2”, “Y3”, “Y4” (Figure 1 )-

[0105] Preferably, the second ends 200b” of the second segments 200b are connected to the movable support 300 by means of respective universal joints.

[0106] More preferably, the connections between the first and second segments 200a, 200b of each arm and the connections between the second segment 200b of each arm and the movable support 300 are made so as to achieve a torsional constraint on each arm. As a result, each arm (in particular each of the two segments 200a, 200b) does not exhibit free torsional movement on itself. Even more preferably, each arm is also configured (sized) to transmit a torsional action, forming a constraint to torsion along the axis of the arm itself. In accordance with an embodiment, at least two of the arms have a torsional constraint.

[0107] In accordance with the preferred embodiment shown in Figure 1 , a first pair of first segments 200a lies on a first plane r1 , and a second pair of first segments 200b lies on a second plane x2. Preferably, the planes r1 , x2 are parallel to each other.

[0108] In such a situation, the second segments 200b” of the first pair are incident in a first virtual center of instantaneous rotation CIR1 , and the second segments 200b” of the second pair are incident in a second virtual center of instantaneous rotation CIR2 (Figure 2).

[0109] The first and second virtual centers of instantaneous rotation CIR1 , CIR2, projected onto the same plane between the first and second planes x1 , x2, are not coincident with each other.

[0110] So as to cause the rotation about the respective main axes of rotation “X1”, “X2”, “X3”, “X4” of the first segments 200a, the manipulator “M” comprises four motors “E” which are activatable independently of one other.

[0111] Each motor “E” is operatively connected to the first end 200a’ of a respective first segment 200a so as to move the respective first segment 200a rotationally about the respective axis of rotation “X1”, “X2”, “X3”, “X4”.

[0112] In other words, by activating one or more motors “E”, it is possible to cause the rotational movement of the corresponding first segments 200a about the respective axis of rotation “X1”, “X2”, “X3”, “X4”. Consequently, the first segments 200a being connected to the second segments 200b, the latter are also moved, causing a movement of the movable support 300.

[0113] The movable support 300 can be translationally moved in the three space dimensions and be rotationally moved about an axis of rotation (which, in the illustrated figures, is an axis perpendicular to the sheet).

[0114] With reference, for example, to Figure 5, two different configurations of the manipulator are noted: one centered (towards the bottom) and one with maximum angular excursion on one side. In particular, in such a figure, the motors “E” have been activated so as to rotate all four manipulator arms about the respective axes of rotation “X1”, “X2”, “X3”, “X4”. In such a situation, two of the first segments 200a are rotated about a positioning axis “G1 ” while the other two first segments 200a are rotated around the other positioning axis “G2”. By doing this, the movable support 300 can be moved along a substantially semicircular trajectory to reach two different positions (visible in Figure 5).

[0115] With reference, for example, to Figures 6A, 6B (but also to Figures 7A and 7B), the motors “E” have instead been activated to cause the rotation about the corresponding axes of rotation “X1”, “X2”, “X3”, “X4” of three of the four first segments 200a from the position shown in Figure 6A to that shown in Figure 6B, the fourth segment 200a being arranged in a substantially unchanged position. In such a situation, the second ends 200b” of the second arms 200b are rotated about the respective axes of rotation “Y1”, “Y2”, “Y3”, “Y4” causing a rotation (thus a change in orientation) of the movable support 300 about an axis of rotation perpendicular to the sheet. In particular, by virtue of the aforesaid movement of the first segments 200a, the movable support 300 rotates in the plane of the sheet (without translating) changing its orientation.

[0116] The present invention achieves the intended objects by overcoming the drawbacks emerged from the prior art.

[0117] In particular, by virtue of the arrangement of the manipulator arms, it is possible to obtain a versatile, reliable, and efficient manipulator. The architecture and structure of the manipulator “M” further allow obtaining a manipulator “M” not affected by kinematic singularities and of small dimensions and weight.

Claims

CLAIMS1. A robotic manipulator (M) having four parallel kinematic arms, in particular a delta robot, comprising:- a support frame;- four manipulator arms each comprising:- a first segment (200a) comprising a first end (200a’) connected to the support frame and a second end (200a”);- a second segment (200b) comprising a first end (200b’) connected, with a connection having at least two degrees of freedom, preferably two degrees of freedom, and even more preferably hinged by a hinge having two degrees of freedom, to the second end (200a”) of the first segment (200a), and a second end (200b”);- a movable support (300) on which an operating member is mounted or mountable, the second ends (200b”) of the second segments (200b) being hinged, preferably by a hinge having at least two degrees of freedom, to said movable support (300); wherein each of said first segments (200a) is connected to the support frame in a rotatable manner about a respective main axis of rotation (X1 , X2, X3, X4) so as to move said movable support (300) and wherein said main axes of rotation (X1 , X2, X3, X4) lie on at least two positioning axes (G1 , G2) parallel to each other.

2. A manipulator according to claim 1 , wherein said at least two positioning axes (G1 , G2) are distinct from each other.

3. A manipulator according to claim 1 or 2, wherein said main axes of rotation (X1 , X2, X3 X4) lie on two distinct and parallel positioning axes (G1 , G2).

4. A manipulator according to claim 3, wherein two of the main axes of rotation (X1 , X2) lie on one of the two positioning axes (G1 ) and whereinthe other two main axes of rotation (X3, X4) lie on the other positioning axis (G2).

5. A manipulator according to any one of the preceding claims, wherein at least two of the first segments (200a) are movable on respective planes (r1 , x2) parallel to and spaced from each other.

6. A manipulator according to any one of the preceding claims, wherein said movable support (300) is made in the form of a rigid body, in particular in the form of a rigid plate or a rigid disc.

7. A manipulator according to any one of the preceding claims, wherein the second ends (200b”) of the second segments (200b) are hinged to the movable support (300) so as to be rotatable about respective axes of rotation (Y1 , Y2, Y3, Y4) parallel to one other.

8. A manipulator according to claim 7, wherein said axes of rotation (Y1 , Y2, Y3, Y4) are parallel to said main axes of rotation (X1 , X2, X3, X4).

9. A manipulator according to claim 7 or 8, when dependent on claim 4 or 5, wherein a first pair of first segments (200a) lies on a first plane (r1) and wherein a second pair of first segments (200a) lies on a second plane (T2), preferably said planes (r1 , x2) being parallel to each other.

10. A manipulator according to claim 9, wherein the second segments (200b”) connected to the first segments of the first pair of first segments (200a) are incident in a first virtual center of instantaneous rotation (CIR1 ) and the second segments (200b”) connected to the first segments (200a) of the second pair of first segments (200a) are incident in a second virtual center of instantaneous rotation (CIR2), and wherein said first and second centers of instantaneous rotation (CIR1 , CIR2), projected on the sameplane as said first or second planes (r1 , r2), are not coincident with each other.11 . A manipulator according to any one of the preceding claims, wherein the second segments (200b) are connected to a same side of the movable support (300), in particular at connection points arranged at the vertices of a quadrilateral other than a rectangle or a square, preferably at the vertices of a trapezium.

12. A manipulator according to any one of claims 1 to 10, wherein at least one of the second segments (200b) is connected to a first side of the movable support (300) and at least another of the second segments (200b) is connected to a second side of the movable support (300) opposite the first side, preferably two second segments (200b) are connected to the first side of the movable support (300) and other two second segments (200b) are connected to the second side of the movable support (300).

13. A manipulator according to any one of the preceding claims, wherein said first segments (200a) of the four manipulator arms all have the same length and / or wherein said second segments (200b) of the four manipulator arms all have the same length.

14. A manipulator according to any one of the preceding claims, comprising four motors (E) activatable independently of each other, each motor (E) being operatively connected to the first end (200a’) of a respective first segment (200a) so as to move in rotation the respective first segment (200a) about the respective axis of rotation (X1 , X2, X3, X4).

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